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Discussion Starter #1
Hi, have 96 Fleetwood and Roadmaster Sedan both with factory clutched mechanical fan and fluid cooler connections. I haven’t confirmed but assuming identical in every way right now.

They both have failure in left end tank. Any recommendations or warnings for either factory plastic aluminum replacements or all aluminum or other aftermarket?

hvac fine in the Cadillac but Buick has no ac engagement or cooling I assume from low refrigerant so it doesn’t trigger the compressor. My guess is if not faulty in some way it is most likely bad from a leak past seal developed from sitting. It was the previous owners deceased dads car they inherited and I thjnk it sat in garage a lot.

any know particular areas they are known to leak or suggestions for bringing them back? I’m gonna go in and have charged with refrig and see what happens but would rather not go in blind.

T
 

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Wow, super restraint there registered 1 1/2 years and just now your first post! Welcome.

Yes, forward upper left side crack on my FWB last Fall, I ordered this = plop n drop:

If you've got a positive pressure left at all, then Plan B is simply get a fill hose kit with a gauge and top it off yourself. If zero charge then Plan A is simply research for a well-reviewed local A/C house (NOT a dealer) and service the whole system including all the special pieces, - rec. de-hyd., orif. tube, blah blah. And even with Plan A of course check for some pressure so you can cut them off at the pass for trying afterward with the, "we found a leak so we had to replace a lot more parts".
 

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I suspect the cooling systems are the same, but you can compare part numbers to ensure that here: cadillac.7zap.com and buick.7zap.com.

I do not have the mechanical fans, but I installed the Liland Global all-aluminum radiator in my Impala several years ago. It fit well and has worked well. I started a thread on here. I recommend it if you can find the one that fits your application.

Regarding the A/C, there are many things that can prevent it from running. I like to start with an electrical inspection. You can learn a lot about the status of your system from the Compressor Checks in this writeup: Auto Air Conditioner Blowing Warm Air, Not Cooling. I agree with Black about topping it off to see what you have. If it works after you add a can, then consider buying a set of A/C gages from Harbor Freight. Comparing the low and high side pressures to a temperature/pressure chart will help you determine what you need to do next.

You can check the Schrader valves for leaks with soapy water, but a can of dye will make any leak glow using a black light. Common places for leaks are the Schrader valves, the hose on the passenger side that rubs on the upper A-arm, and the compressor body itself. The best way to determine if the system is sealed is to connect a vacuum pump to it and see if it will hold vacuum for at least 30 minutes. They are relatively cheap at Harbor Freight and work well.

If you decide to just take it to a shop, watch a couple youtube videos on A/C troubleshooting and repair so you have an idea what to expect. Good A/C work is not cheap, and cheap A/C work is usually not good, I learned that the first time I had a 'tech' fix mine at his house. Cost me hundreds of dollars in parts after I got the car back from him. That is when I decided to learn how to do it myself.
 

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Alright guys make sense. I have enough vehicles to invest in the equipment mentioned. I’ll use your advice and my pretty good automotive common sense to ‘get there from here’ I’ll report back. Thanks
 

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I put a 20oz can of 134, pag, stop leak combo in the Buick. To my surprise it’s like i hit the easy button. Low side pressure came up from below green arc to about middle of green arc. Cooling is in low 40s regardless of outside temp... 80-105 or so. I run the thing every time I drive to keep the system active.
I installed a Murray 432396 oreillys in it with no issues. Couldn’t be easier. That should be the plastic aluminum with two heat exchangers driver side oil and passenger side atf iirc.

I had to ship in a Murray plastic copper for the Cad. 438035 should be the part number. MN to CA the biz was beat up, some of the fins had been hit. I’m going to straighten them, but tried to return and was told I’d have to ship in any alternatives including the part number I put in the Buick. The one in the Buick was already local and was pristine.

the copper and aluminum cores looks the same. I guess they are coated with something? Anyhow I’ve heard copper will reject more btu but Aluminum is lighter. They both seem about the same. These are both single row, seem the same as what came out of Buick. I think Cad is the same. I don’t think either car has the higher coolant or cooling capacity rads, but I’ll double check the rads themselves and the codes on the sticker under the trunk lid.

btw they didn’t have Stant Tstats so I boughta Murray part number I can share if needed but a 180*. Body of tstat has motorad stamped on it and it runs 10 degree cooler than the stars in boththe Buick and the Cad which run at 179-181 running down the highway regardless of ambient. Buick now runs 169-171. I’m not happy about that. Going to put identical Stant part numbers in both.
 

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Discussion Starter #6 (Edited)
Buick overnight went to cycling the compressor briefly every 5-10 seconds with no cooling. I had pulled previous owner stuff looked like small ball of black rtv from the high side port. It leaked less but still leaked slowly after i cinched down the valve core. With cap on tight I could not hear any leak. I pulled the high side cap a short time ago and heard no leak. I put simple gage on the low side with comp cycling and low was a bit lower than green and higher was above green, compressor just keeps cycling. I tried putting 134 in from a full 12 oz can and it almost seems it didn’t draw in much if any but low side needle sweep came up into green, comp keeps cycling with no cooling of the cabin, vent tstat shows ambient more or less.
What’s likely my issue? It cooled fine daily for two weeks no change in vent output temp. Low 40s ... then this. What do you think, bad pressure switch? Did I damage something? I should add the compressor never engaged or cycled before I added 20 oz two weeks ago. Now it seems to still have more or less same amount of refrig in it, but just quick cycles. Early on in the initial refill the compressor engaged and stayed engaged while the system immediately started cooling. I’ve had temp set at 60 both times with ambient in 70s.
 
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